Download or read book Contribution of Steel Fiber in a Small Scale Reinforced Concrete Beam written by Nonih Gampuhur and published by . This book was released on 2015 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since today, fiber reinforced concrete is one of the most realistic materials to develop the use of concrete in load-bearing structure. The hooked-end steel fiber with two different the aspect ratio were used in this study. They are 65 mm aspect ratio with 0.55mm in diameter and 35 mm in length and 0.75 mm in diameter, 60 mm in length with 80 mm in aspect ratio. The volume fraction for both of steel fiber used is 1%. There are four concrete batches and each of batches consists of 3 beam specimens with dimension 750 mm x150 mm x150 mm and 6 cube specimens with 150 mm x 150 mm x 150 mm dimension. The beams were tested at 28 days under two-point load. The result showed that the addition of steel fiber in concrete improved the first cracking load, ultimate load, and ductility of the concrete beam. In comparison in terms of concrete compressive strength, SF35 improved for 12.94% and SF60 improved for 26.51% at 7days. Meanwhile, the compressive strength improved for 14.15% and 23.58% at 28 days for SF35 and SF60, respectively. The first crack (Pcr) was determined for the result obtained in experimental and SFRC showed significant increases to first crack load over conventional reinforced concrete beam. The SFRC beam with SF35 increased for 56.33% and SF60 for 68.67% for ultimate load (Pu), when compared to conventional reinforced concrete beam. This shows that longest SF was effective in resisting beam ultimate load compared with shortest SF.

Download or read book Investigation of Strength enhancement Mechanism and Size Effect on Ultimate Shear Strength of Steel Fiber Reinforced Concrete SFRC Slender Beams written by Mohammad Reza Zarrinpour and published by . This book was released on 2019 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research study consists of two separate phases. In the first phase, an experimental study was conducted to identify the shear-enhancement and failure mechanisms behind the ultimate shear strength of steel fiber-reinforced concrete (SFRC) slender beams by utilizing the full field deformation measuring capability of digital image correlation (DIC) technology. A total of 12 large-scale simply supported SFRC and RC beams with a range of heights including 12 in. (305 mm), 18 in. (457 mm), 24 in. (610 mm),36 in. (915 mm), and 48 in. (1220 mm) were tested under monotonic point load. The greater shear strength in SFRC beams stems from the fiber bridging effect which delays the propagation of the cracks into the compression zone. In contrast to the traditional assumption for either plain concrete or SFRC beams, where the shear contribution resulting from dowel action is completely neglected, this research clearly shows that the dowel action has an appreciable effect on the ultimate shear strength. Its contribution varies from 10% to 30% as the beam depth increases from 12 in. (305 mm) to 48 in. (1220 mm). On the other hand, the compression zone's contribution decreases from 69% to 36%with the increase in beam depth. In addition, the shear contribution from the fiber bridging effect along the critical shear crack stays virtually unchanged at 20%, regardless of beam depth. In this study, the minimum shear strength obtained was in the range of 5 SQRT (f'c) psi (0.42 SQRT (f'c) MPa) for the beams with the greatest depth. This indicates that the maximum allowed shear stress limit of 1.5 SQRT (f'c) psi (0.125 SQRT (f'c) MPa) specified in ACI 318-14 is on the very conservative side. While the size effect on ultimate shear strength of plain concrete beams has been well researched in the past decades, limited tests were carried out to study the extent and mechanism of size effect in steel fiber-reinforced concrete (SFRC) beams. Current American Concrete Institute's ACI 318 Building Code restricts the use of steel fiber as minimum shear reinforcement to beams with a height up to 24 in. (610 mm). In the next phase of the study, in addition to the analyzing of the current testing data, the laboratory test results from the first part of the study and the respective digital image correlation (DIC) images were examined to identify the underlying factors that cause size effect on ultimate shear stress of SFRC slender beams. Moderate size effect was observed in the beams tested in this study. Through the full field strains and a mechanical based analysis, it was found that the size effect is a function of both the beam height and the shear span length.In larger beams, due to the greater horizontal and vertical distance from the compression zone to the supports, the critical diagonal shear crack was able to propagate deeply into the top of the beams. As a consequence, the compression zone exhibits less contribution to shear resistance in larger size beams, and the dowel action becomes more critical. Therefore, a minor flaw in dowel zone such as lacking well-distribution of steel fibers results in early destruction of dowel resistance and shear failure.

Download or read book On Shear Behavior of Structural Elements Made of Steel Fiber Reinforced Concrete written by Estefanía Cuenca and published by Springer. This book was released on 2014-12-27 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book sheds light on the shear behavior of Fiber Reinforced Concrete (FRC) elements, presenting a thorough analysis of the most important studies in the field and highlighting their shortcomings and issues that have been neglected to date. Instead of proposing a new formula, which would add to an already long list, it instead focuses on existing design codes. Based on a comparison of experimental tests, it provides a thorough analysis of these codes, describing both their reliability and weaknesses. Among other issues, the book addresses the influence of flange size on shear, and the possible inclusion of the flange factor in design formulas. Moreover, it reports in detail on tests performed on beams made of concrete of different compressive strengths, and on fiber reinforcements to study the influence on shear, including size effects. Lastly, the book presents a thorough analysis of FRC hollow core slabs. In fact, although this is an area of great interest in the current research landscape, it remains largely unexplored due to the difficulties encountered in attempting to fit transverse reinforcement in these elements.

Download or read book Shear Behavior of Steel Fiber Reinforced Prestressed Concrete Beams Without Shear Reinforcement written by Jae-Sung Cho and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The ACI 318-08 building code allows to use the steel fiber reinforcement as alternative shear reinforcement with satisfying certain criteria when a beam is required minimum shear reinforcement. However, this provision applies to a nonprestressed and prestressed concrete beam such that it could be conservative since the shear strength of prestressed concrete beam is generally enhanced due to the prestressing force. This is due partially to the fact that the provision has been accepted based on researches, mostly conducted in nonprestressed concrete beam. Most of experiments conducted for prestressed concrete beam in small scale tests, with a height of specimens were less than 10 in. A larger scale of experiment is required due to concerns of size effect. In addition, in order to evaluate the qualification of a Steel Fiber Reinforced Concrete (SFRC) mixture used for structural applications, such as increasing shear resistance, a material evaluation method is essential. Currently ASTM or ACI Committee 544 (Fiber-Reinforced Concrete) does not recommend any standardized test method for evaluating shear performance of a particular SFRC material. This study addresses the research gaps described above by testing large-scale Steel Fiber Reinforced Prestressed Concrete (SFRPC) beams as well as developing a simple laboratory test techniques. A total 13 simply-supported beams for large-scale test with a shear span to effective depth ratio of 3.0 and a height of 24 in. were subjected to monotonically-increased, concentrated load. The test parameters were mainly included compressive strength, volume fraction of steel fibers, compressive reinforcement ratio. The results of large-scale test showed that the use of hooked steel fibers in a volume fraction greater than or equal to 0.50% volume fraction of steel fibers (67 lb per cubic yard), which is less than requirement by ACI 318-08 (0.75%, 100 lb per cubic yard), led to substantial enhancement of shear behaviors including the first cracking, the ultimate, and ductility. High compressive strength of SFRC, greater than 9000 psi, which is higher than ACI 318-08 requirement (less than 6000 psi) could be used as well. However, there was no significant effect from compressive reinforcement ratio. A simply shear test method for SFRC was proposed in this study. The test apparatus is almost exactly the same as the conventional ASTM bending test with only minor modification, in addition, it could simulate a pure shear stress by adjusting loading and support positions. By introducing a proper reinforcement for bending stress, it was possible to evaluate shear performance of SFRC with clear and uncomplicated shear stress field in the critical section.

Download or read book Ultra High Performance Concrete UHPC written by Ekkehard Fehling and published by John Wiley & Sons. This book was released on 2015-04-20 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Selected chapters from the German concrete yearbook are now being published in the new English "Beton-Kalender Series" for the benefit of an international audience. Since it was founded in 1906, the Ernst & Sohn "Beton-Kalender" has been supporting developments in reinforced and prestressed concrete. The aim was to publish a yearbook to reflect progress in "ferro-concrete" structures until - as the book's first editor, Fritz von Emperger (1862-1942), expressed it - the "tempestuous development" in this form of construction came to an end. However, the "Beton-Kalender" quickly became the chosen work of reference for civil and structural engineers, and apart from the years 1945-1950 has been published annually ever since. Ultra high performance concrete (UHPC) is a milestone in concrete technology and application. It permits the construction of both more slender and more durable concrete structures with a prolonged service life and thus improved sustainability. This book is a comprehensive overview of UHPC - from the principles behind its production and its mechanical properties to design and detailing aspects. The focus is on the material behaviour of steel fibre-reinforced UHPC. Numerical modelling and detailing of the connections with reinforced concrete elements are featured as well. Numerous examples worldwide - bridges, columns, facades and roofs - are the basis for additional explanations about the benefits of UHPC and how it helps to realise several architectural requirements. The authors are extensively involved in the testing, design, construction and monitoring of UHPC structures. What they provide here is therefore a unique synopsis of the state of the art with a view to practical applications.

Download or read book Flexural Behavior of Steel Fiber Reinforced Prestressed Concrete Beams and Double Punch Test for Fiber Reinforced Concrete written by Netra Bahadur Karki and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Steel fibers have widely been used in the past to reinforce brittle materials in many nonstructural applications such as pavement, tunneling lining, etc. On the basis of numerous previous studies, ACI 318-11 [2011] has recently accepted steel fiber as a minimum shear reinforcement replacement with minimum 0.75% volume fraction for both reinforced concrete and prestressed concrete members. However, not much previous research has talked about the flexural behavior of fiber reinforced concrete (FRC). As per ACI 318-11 for tension-controlled sections, the net tensile strains in the outermost layer of steel, et, should be greater than or equal to 0.005 and for the moment redistribution in continuous beam the section should sufficiently ductile (et [greater or equal to] 0.0075). For this, the sections should have small longitudinal reinforcement ratio which ultimately leads to an inefficient beam section with a large cross-sectional area. In contrast, the use of smaller concrete cross sections can lead to a diminished ductile flexural behavior as well as premature shear failure. In this context, the use of steel fiber reinforced concrete could be a potential solution since fiber can increase both the concrete shear strength and it's usable compressive strains. However limited previous researches on the flexural behavior on SFRC beams are available and most of them are of small scales and concentrated only basically for shear behavior. To the best of our knowledge, the large-scale prestressed fiber reinforced concrete beam specimens have yet to be studied for flexure behavior. In this project, six large scale prestressed concrete beams with or without steel fiber along with some material test were tested. Our experimental investigations indicated that even with inclusion of small percentage volume of fraction of steel fiber (Vf =0.75%) could not only increase the ductility and shear strength of the SFRPC beam but also change the failure pattern by increasing usable strain in concrete and steel. A modification on the limit for c/dt ratio and [phi] factor for design of flexural member given in current ACI could be proposed which could imply the smaller sections with higher longitudinal reinforcement ratio and less shear reinforcement. could be used. Any standard material test results have to ensure that FRC has, at least, been batched properly and it can give indications of probable performance when used in structures. In the current material testing method suggested by ACI, the third point bending test (ASTM C1609) has an inherent problem in that the coefficients of variations for post cracking strength and residual strength are generally very high on the order of 20%. The direct tensile test can be a more appropriate material. However, it is currently not recommended as standard method in the U.S. Because of it's difficultly in gripping arrangement which will lead to cracking of the specimen at the grips. Both the test methods also require close loop servo controlled machine. The round panel test method (ASTM C1550) requires large size specimen and heavy steel supports prevents performing test in small laboratories. Split cylinder test (ASTM C496), do not necessarily reflect the true properties of the material as the specimen is forced to fail in the line of the application of the load and the test method is also not recommended by ACI for SFRC. In order to improve the material assessment procedure, the double Punch Test (DPT) introduced by Chen in 1970 [Chen, 1970] was extensively evaluated to develop a simple, quick and reliable testing method for SFRC. Various tests were carried out in order to evaluate peak and residual strength, stiffness, strain hardening and softening, toughness and other post crack properties. Our test results indicated that the DPT method could be immersed as reliable, easier and economical material test method. It could be used to distinguish the peak strength, residual strength, toughness stiffness and crack resistance, of different SFRC mixtures with less scatter results compared to other material test methods.

Download or read book ACI 318 19 Building Code Requirements for Structural Concrete ACI 318 19 and Commentary ACI 318R 19 written by ACI Committee 318 and published by . This book was released on 2019-05 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Shear Stress on Full Scale Steel Fiber Reinforced Concrete Beams written by Blair A. Schantz and published by . This book was released on 1993 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structural Applications of Steel Fiber Reinforced Concrete Analysis and Design written by Abdeslam Reklaoui and published by . This book was released on 1988 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Modeling of Concrete Cracking written by Guenter Hofstetter and published by Springer Science & Business Media. This book was released on 2011-10-08 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents the underlying theories of the different approaches for modeling cracking of concrete and provides a critical survey of the state-of-the-art in computational concrete mechanics. It covers a broad spectrum of topics related to modeling of cracks, including continuum-based and discrete crack models, meso-scale models, advanced discretization strategies to capture evolving cracks based on the concept of finite elements with embedded discontinuities and on the extended finite element method, and extensions to coupled problems such a hygro-mechanical problems as required in computational durability analyses of concrete structures.

Download or read book Advances in Civil Engineering and Building Materials written by Shuenn-Yih Chang and published by CRC Press. This book was released on 2012-10-31 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Civil Engineering and Building Materials presents the state-of-the-art development in: - Structural Engineering - Road & Bridge Engineering- Geotechnical Engineering- Architecture & Urban Planning- Transportation Engineering- Hydraulic Engineering - Engineering Management- Computational Mechanics- Construction Technology- Buildi

Download or read book Steel Fiber Reinforced Concrete written by Harvinder Singh and published by Springer. This book was released on 2016-10-26 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses design aspects of steel fiber-reinforced concrete (SFRC) members, including the behavior of the SFRC and its modeling. It also examines the effect of various parameters governing the response of SFRC members in detail. Unlike other publications available in the form of guidelines, which mainly describe design methods based on experimental results, it describes the basic concepts and principles of designing structural members using SFRC as a structural material, predominantly subjected to flexure and shear. Although applications to special structures, such as bridges, retaining walls, tanks and silos are not specifically covered, the fundamental design concepts remain the same and can easily be extended to these elements. It introduces the principles and related theories for predicting the role of steel fibers in reinforcing concrete members concisely and logically, and presents various material models to predict the response of SFRC members in detail. These are then gradually extended to develop an analytical flexural model for the analysis and design of SFRC members. The lack of such a discussion is a major hindrance to the adoption of SFRC as a structural material in routine design practice. This book helps users appraise the role of fiber as reinforcement in concrete members used alone and/or along with conventional rebars. Applications to singly and doubly reinforced beams and slabs are illustrated with examples, using both SFRC and conventional reinforced concrete as a structural material. The influence of the addition of steel fibers on various mechanical properties of the SFRC members is discussed in detail, which is invaluable in helping designers and engineers create optimum designs. Lastly, it describes the generally accepted methods for specifying the steel fibers at the site along with the SFRC mixing methods, storage and transport and explains in detail methods to validate the adopted design. This book is useful to practicing engineers, researchers, and students.

Download or read book Fibrous Concrete written by Concrete Society and published by . This book was released on 1980 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structural Applications of Fiber Reinforced Concrete written by Nemkumar Banthia and published by . This book was released on 1999 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Steel Fibers as Web Reinforcement in Reinforced Concrete written by Gilbert R. Williamson and published by . This book was released on 1978 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this investigation was to determine the feasibility of replacing shear reinforcement (stirrups) with randomly distributed steel fibers for the prevention of diagonal tension (shear) failure in full-scale conventionally reinforced concrete beams. The following conclusions are based upon the use of steel fibers with deformed ends (Dramix) to replace stirrups: (1) Steel fibers can be used to replace stirrups in beams with no reduction in the ultimate design moment capacity; (2) Steel fibers increase the shear strength of concrete beams sufficiently to prevent catastrophic diagonal tension failure, while forcing the beam to fail in flexure; (3) ACI Code procedures can be used without modification to design reinforced concrete beams that contain steel fibers as shear reinforcement; (4) Low volume percentages of steel fibers have no effect upon the stiffness of full-scale beams; and (5) Steel fibers present a potentially more economic alternative to the use of stirrups in reinforced concrete design.

Download or read book The Effect of Fiber Corrosion on Shear Capacity of Steel Fiber Reinforced Concrete Beams and an Initial Investigation on Alkali silika Reaction in Steel Fiber reinforced Concrete written by Regina Nyambura Waweru and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The first part of this research aims to investigate the effect of fiber corrosion on the shear capacity of Steel Fiber Reinforced Concrete beams. It will also strive to determine at what reduction in minimum diameter of the fiber does the effect of corrosion become most severe on the shear capacity of the beam. Four simply-supported beams with a shear span to depth ratio of 3.3 were subjected to a monotonically increasing load. The targeted concrete compressive strength for all beams was 6000 psi. This however differed from the measured strength due to a number of factors as will be discussed in the paper. The fixed parameters for the experiment were the beam size, shear span-to-effective depth ratio, and concrete compressive strength, while the varied parameters were the fiber content and the extent of corrosion of the steel fibers. Pre-corroded fibers were used in this research to give the worst case scenario because in real life situations, only the fibers closest to the surface of the concrete (0.10 in. from surface) or those close to a crack will be corroded. Hooked steel fibers were used at a volume fraction of 0.75% with an aspect ratio of 125 and a length of 1 in. Small specimen tests were also conducted to determine the change in the mechanical properties of SFRC at different levels of corrosion. The tests conducted were: the three point loading test, the compression test and the fiber pullout tests. Test results revealed that a 12.5% reduction in the minimum fiber diameter, has almost no effect on the shear capacity of beams. Results from the fiber pullout tests showed a slight increase in the pullout load which seems to indicate an increase in the bond between the fiber and cementitious matrix. However, for beams with a 50% reduction in the minimum fiber diameter a 24% reduction in the shear strength of the beam was witnessed. These observations indicated that the type of failure for these beams was through fiber breakage before pullout. The results from the fiber pullout specimens also seemed to support this failure mode as 80% of the fibers broke before pullout. Finally recommendations are made for more future research on the topic. The second part of the thesis covers the initial investigation on alkali-silica reaction (ASR) in SFRC. Most importantly, it tries to determine whether the addition of fibers to concrete can actually arrest cracks due to ASR in concrete and thus counteract its effect on the durability of the structure. Four beams with dimensions of 20 x 6 x 6 in. were cast using reactive aggregates, in accordance to ASTM C1260 and C1293 and subjected to an accelerated ASR test. Two beams were reinforced with 1% fibers while the control specimens had no fibers. From the preliminary observations on the beams by measuring their elongation, the SFRC beams showed less expansion compared to the plain concrete beams. Based on these these initial findings, a more intense research was recommended on the effect of steel fibers on ASR. This is an ongoing research that will take a couple of years as the specimens with reactive aggregates will be cast and put in the natural environment for cracking to occur due to ASR. The specimens will then be compared with their counterparts with no fibers to reach a conclusion.

Download or read book Mechanics of Fiber and Textile Reinforced Cement Composites written by Barzin Mobasher and published by CRC Press. This book was released on 2011-09-20 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: Among all building materials, concrete is the most commonly used-and there is a staggering demand for it. However, as we strive to build taller structures with improved seismic resistance or durable pavement with an indefinite service life, we require materials with better performance than the conventional materials used today. Considering the enor